Insects Damaging Canes and Shoots

Periodical Cicada, Magicicada septendecim (L.)

Other Cicadas Magicicada cassinii (Fisher) and Magicicada septendecula Alexander and Moore (Homoptera: Cicadidae)

Sounds:

Adult females of cicadas injure grapevines by making ovipositional slits in the canes. The canes then may break at the slits during the season in which they are made or during the subsequent year. Because of such breakage, the resultant crop and vine growth may be affected adversely.

Nymphs of periodical cicadas do not feed to any large extent on the roots of grape. Once the nymphs emerge from the eggs, they move into the ground, where they feed on the roots of deciduous trees. These nymphs require 17 years to complete development and emerge from the ground as adult cicadas. Adults emerge during late May and are present for about six weeks. The adult is about 1/2 inches long and has clear wings and a dark body accented with orange and red.

Four different broods of cicadas occur in Ohio. Although each brood requires 17 years to complete its life cycle, the broods overlap, and adult cicadas emerge at intervals of two to eight years in different areas of the state.

Expected Emergence Dates

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Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

Snowy Tree Cricket, Oecanthus fultoni T.J. Walker (Orthoptera: Gryllidae)

Sound:

Ohio Snowy Tree Cricket

The snowy tree cricket damages grapevines primarily through its ovipositional activities. During late summer or early fall, the female cricket makes a series of punctures in a grape cane, which is usually growth of the current season. She then lays an egg in each hole. Eggs hatch late the following spring and the young crickets are predaceous during most of their lives, occasionally feeding on a variety of vegetation when they are nearly completely developed. Adults are strictly plant feeders. By late summer, the crickets achieve the adult stage. The adult tree cricket is slender, 5/8 inch long and pale green, and has antennae that are considerably longer than its body. There is only one generation per year.

Canes may break at the ovipositional punctures and additional injury may take place if disease organisms enter the cane through the egg punctures; however, extensive damage attributable to this insect is not common. Vineyards most likely to be infested are those with large amounts of natural ground cover or cover crops, which provide food and shelter for the crickets.

Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

European Fruit Lecanium, Lecanium corni Bouche (Homoptera: Coccidae)

The European fruit lecanium belongs to a group of scale insects known as the soft scales or unarmored scales; the protective covering of the lecanium consists of the thickened body wall itself instead of a separate structure, as in the armored scales.

Mature female scales attach themselves to l-year-old grape canes in early spring. Scales are about 5/16 inch long and dark brown with a powdery coating. During June, the female scale lays eggs to the extent that they fill the cavity occupied by the female. Once the female completes oviposition, she dies. During July and August, crawlers emerge from the eggs and move to grape leaves, where they position themselves temporarily on upper leaf surfaces. The young scales suck juices from the leaves. By late summer, the females crawl back to the canes, where they overwinter as oval scales. Growth is completed in late spring.

The European fruit lecanium does not often cause extensive damage to grapes.

Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

Grape Mealybug, Pseudococcus maritimus (Ehrhorn) (Homoptera: Pseudococcidae)

The grape mealybug is a common pest of grapes. The adult mealybug is 1/8 inch long and cottony white. Although the mealybug does not ordinarily occur in numbers great enough to cause serious injury, individuals can always be found in vineyards. Mealybugs remove sap from the plant and deposit honeydew on the leaves and fruit, which act as a medium for sooty mold development.

The mealybug overwinters as an immature form (first instar) within a cottony mass produced by the female. During April and May, the young mealybugs become active, sucking sap from the new shoots. Development is completed by late June and the adult female lays eggs within a cottony structure, an ovisac. Eggs hatch in a few days, and the small mealybugs start to feed, many finding their way into the clusters and removing sap from stems and pedicels of the clusters. By late August, the mealybugs reach maturity and lay eggs, which give rise to the overwintering population of mealybugs. Eggs that do not hatch before the onset of cold weather in the fall do not survive winter.

Mealybugs have several natural ene-mies. A parasitic wasp and a predaceous insect attack the eggs. All stages of the mealybug are prey for ladybugs.

Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

Grape Scale, Diaspidiotus uvae (Comstock) (Homoptera: Diaspididae)

Grape scale is not a common insect in Ohio, existing only in the southern part of the state. The insect occurs, to a very limited extent, on forest and shade trees, though records show serious injury only to grapes.

Mature scales are flat, elliptical and about 1/15 inch in diameter. They are pale yellowish-brown with a pale yellow nipple to one side of center. The wingless female scale overwinters in nearly full-grown form and completes growth in the spring. During May and June she gives birth to 35-50 living young. As with all armored scales, the life of this insect, with the exception of the short period of activity of the young and the winged male, is passed under the protection of the waxy scale cover. Scale infestations are located on 2-year-old wood. When severe, grape scale infestations can retard development of the vines.

Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

Grape Cane Gallmaker, Ampeloglypter sesostris (LeConte) (Coleoptera: Curculionidae)

The grape cane gallmaker is a small, brown snout beetle, about 1/8 inch long and closely related to the grape cane girdler. Adult beetles overwinter in wooded and brushy areas close to vineyards. During May the beetles emerge from their hibernation quarters. The female gallmaker chews a row of holes along the length of a shoot, just above a node. She places an egg in the hole closest to the node. A reddish swelling, or gall, develops in the shoot, and the larva feeds within the shoot area that is affected. The swelling is usually about 3/4-1 inch long.

Female beetles deposit eggs from late May through June, beginning when the shoots are 10-20 inches long. The larvae are fully developed by late July and pupate inside the galls. New adult beetles emerge during August and seek overwintering areas in late summer and fall. One generation occurs each year.

Most of the galls are produced beyond the grape clusters, so loss of crop is slight. Canes having the galls are able to produce and bear a crop the following season. If the grower desires to remove galls by pruning, action should be taken before mid-July as the beetles will begin to leave the galls by that time.

Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

Grape Cane Girdler, Ampeloglypter ampelopsis (Riley) (Coleoptera: Curculionidae)

The grape cane girdler is a small, black snout beetle about 1/8 inch in length. The insect strongly resembles the grape cane gallmaker. It overwinters as an adult underneath leaves and other trash in and around vineyards. Adult girdlers emerge during late May and early June.

When new grape shoots are 15 to 20 inches long and usually before bloom, the female beetle chews two series of holes around a shoot. These girdles are a few inches apart. The beetle then deposits a single egg in the girdle closest to the vine trunk. The larva that hatches from this egg feeds in the shoot pith between the girdles. Eventually, the shoot breaks and falls off at the outer girdle, leaving the infested section on the cane. The infested section of the shoot remains attached but may fall off later.

Larvae complete development during July and pupate within the shoots. The new adults exit from the shoot sections in August and overwinter. There is one generation of the grape cane girdler each year.

Economic loss due to the cane girdler ordinarily is not a major concern on mature vines. The girdles most often are made in a portion of the shoot beyond where the clusters are formed, so fruit loss is rare. However, where a concentration of girdled canes are observed in a vineyard, it is surely alarming and often causes undue concern. Nevertheless, injury may be important on newly planted or young Vines.

Removing infested shoots may be of some benefit as a control procedure.

Such affected shoots should be cut off below the lower girdle before the beetles emerge in late July or August.

Current pesticide recommendations may be found at http://www.hort.purdue.edu/hort/ext/extpubs.shtml

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